JOI2016本選

t1.cpp

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define PB push_back
#define PPB pop_back
typedef pair<int, int> pii;
static const int INF = 1LL<<61;
static const int MAX_N = 20005;
static const int MAX_M = 1005;

int n, m, k, dp[MAX_N], A[MAX_N];

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  cin >> n >> m >> k;
  for (int i = 0; i < n; ++i) {
    cin >> A[i];
  }

  fill(dp, dp + MAX_N, INF);
  dp[0] = 0;
  for (int i = 0; i < n; ++i) {
    int tmax = 0, tmin = INF;
    for (int j = 1; j <= m && i + j <= n; ++j) {
      tmax = max(tmax, A[i + j - 1]);
      tmin = min(tmin, A[i + j - 1]);
      dp[i + j] = min(dp[i + j], dp[i] + (k + j * (tmax - tmin)));
    }
  }

  cout << dp[n] << endl;

  return 0;
}